The Rebbe advises to shift focus entirely to positive matters, especially words of Torah, as even a little light dispels much darkness. He suggests immersion in the mikvah (Tvilas Ezra), daily charity before prayer, and regular study of Chumash, Tehillim, and Tanya as established by the Previous Rebbe, all without making a vow.
https://www.torahrecordings.com/rebbe/igroskodesh/015/010/5516